Please help advise me on building a RAM tester

Feb 18, 2005 5 Replies
J

I posted this to a few different newsgroups, sorry for the triple postings, I wasn't sure of the most appropriate place to post.



Since I can't find anything on the 'net that will test them, I am considering building a RAM tester, specifically a 4116 DRAM tester. It is a very old form of RAM. To those of you that may not remember it, the pinouts are



___ ____ -5v -|1 \_/ 16|- Gnd Din -|2 15|- /CAS /WE -|3 4 14|- Dout /RAS -|4 1 13|- A6 A0 -|5 1 12|- A3 A2 -|6 6 11|- A4 A1 -|7 10|- A5 +12v -|8 9|- +5v -----------


I admit up front, I have no background in this type of stuff, but I do have a willingness to try. My long range general idea so far is to have a fairly large breadboard with 25 ZIF sockets on it (to test 25 at once). From there, wire the appropriate voltage pins to a common point so I can supply power via a switching power supply. That in itself is probably enough of a challenge for me, but assuming I can do that (and that's a pretty big assumption), then what? I'd like to have it interface with a PC to run a program to test the RAMs at various speeds. I know pretty vague, but that's where I'm looking for your input.



Thoughts? Ideas? Advice? Any comments appreciated. Thanks,



Joe



snipped-for-privacy@ameritech.net


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I

Hmm. Inputs: 7 address + 2 strobes + 1 enable + 1 data = 11 pins. Outputs: 1 pin.

There are 12 outputs and 4 (?) inputs from a standard parallel port. At 100Khz rep rate, that's 320ms or so to read/write the entire chip. Write 1, read, write 0, read, write 'random pattern' (to check 'stuck at'), read.

Maybe 2 seconds. Oh, connect 4 chip outputs to the PP inputs, and you're testing them way, way faster than you can plug them in. This will catch 99.99% of errors.

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C

postings,

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pinouts

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With DRAM timing is critical for proper operation, any test that doesn't test this aspect is useless. The simple way is to find a piece of equipment that uses them and test by substitution, even that is a very poor test.

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M

Wasn't the 4116 used in some early video arcade games? If it was the people who collect and repair the old games might be interested in the chips. I remember a lot of static damaged memory from careless handling of the 4116 chips.

Beware of those who suffer from delusions of adequacy! Michael A. Terrell Central Florida
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R

"Joe Magiera" a écrit dans le message de news:

3b7Rd.8823$ snipped-for-privacy@newssvr33.news.prodigy.com...

A very low cost and easy solution : Buy an old Apple II or Apple II+ (but not an Apple IIe !), which is equipped with 3x8 4116 RAM sockets for a great

48Ko total. Remove the top 16 of these 24 original RAM chips and put your RAM to be tested in these sockets, and run one of the "RAM test" software the used to be available for the Apple II... You will have an indication of the failing chip if any...

Friendly,

Robert Lacoste ALCIOM - The mixed signal experts www.alciom.com To contact us, thanks to click on the antispam link below : http://www.cerbermail.com/?dCSHUxvwpw
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C

Just buy some new ones on ebay.... No bids so far... 50 for $1 perhaps

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